Vauxhall’s most powerful diesel engine ever is now available in the Insignia range, producing 195PS and 400Nm of torque, but with CO2 emissions as low as 129g/km.

Known as the Insignia BiTurbo, and on sale now, it’s available with a choice of five-door Hatch and Sports Tourer bodies in SRi, SRi Vx-line and Elite trims, priced from £27,120 on the road.

The potent, twin-sequential turbocharged diesel is based on the existing 1956cc unit which powers key models in the Insignia, Astra and new Zafira Tourer range. However, in BiTurbo form the engine produces up to 35PS more power and a significant 50Nm of extra torque, reducing the 0-60mph time by nearly one second to 8.2 seconds (Insignia FWD Hatch).

But thanks to a package of eco features – including standard Start/Stop across the range – the FWD Hatch achieves a combined 57.6mpg, 2.2mpg better than the single-turbo 2.0 CDTi 160PS model.

What makes the Insignia BiTurbo unique in this class is its use of sequential turbocharging, with the smaller turbo accelerating quickly at lower engine speeds to eliminate “lag”, providing 350Nm of torque from just 1500rpm. In the mid-range, both turbochargers work together, with a bypass valve allowing gases to flow from the small to large unit; during this phase, maximum torque of 400Nm is produced between 1750-2500rpm. From 3000rpm, all gases flow directly to the larger turbo, ensuring performance is maintained at higher engine speeds.

Complementing this power gain, Vauxhall’s clever FlexRide adaptive damping is standard on all Insignia BiTurbos (normally a £790 option on front-wheel drive Insignias). The system reacts within milliseconds to driver inputs and can ‘learn’ how the car is being driven and adapt damper settings accordingly. Drivers can also select Tour and Sport buttons, and configure the throttle, steering and damper settings in Sport mode separately.

On four-wheel drive models, FlexRide is integrated with the car’s Torque Transfer Device (TTD) and the rear axle’s electronically controlled Limited Slip Differential (e-LSD). These features allow torque to be automatically transferred between front and rear wheels, and between left and right wheels on the rear axle, offering exceptional levels of traction, grip and control.

In common with other models in the Insignia range, the BiTurbo has the option of Vauxhall’s new Front Camera System, with traffic sign recognition and lane departure warning, and Adaptive Cruise Control, which allows the driver to maintain a set distance from the car in front.